A driveline disconnect clutch may open and close to selectively isolate portions of a driveline from vehicle wheels. For example, a driveline disconnect clutch may be positioned between an engine and a driveline integrated starter/generator to allow the engine to operate with the driveline integrated starter/generator, or alternatively, separately and in isolation from the driveline integrated starter/generator. The driveline disconnect clutch may be closed during higher driver demand torques to provide driveline torque that matches the demand torque. The driveline disconnect clutch may be opened at lower demand torques so that the engine may be stopped to conserve fuel. However, closing the driveline disconnect clutch may cause torque disturbances in the driveline if the driveline disconnect clutch transfers more torque than is desired in a short period of time.
The inventors herein have recognized the above-mentioned disadvantages and have developed a driveline disconnect clutch adaptation method, comprising: rotating a transmission input shaft at a first speed; operating an engine in a speed control mode and rotating the engine at a second speed different from the first speed; adjusting a transfer function in response to a torque estimate based on engine operating conditions; and operating a driveline disconnect clutch in response to the transfer function.
By adjusting an application force of a driveline disconnect clutch in response to a torque estimate based on engine operating conditions, it may be possible to reduce the possibility of transferring more torque than is desired over a short time interval. Consequently, the possibility of a driveline torque disturbance that is related to closing the driveline disconnect clutch may be reduced. Additionally, driveline disconnect clutch torque may be estimated without the cost of a torque sensor.
The present description may provide several advantages. Specifically, the approach may reduce driveline torque disturbances of a hybrid driveline. Further, the approach may improve vehicle drivability. Further still, the approach may reduce driveline wear, thereby increasing the operating life of the driveline.
The above advantages and other advantages, and features of the present description will be readily apparent from the following Detailed Description when taken alone or in connection with the accompanying drawings.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.